A method and a device for manufacturing a flexible strip of at least two different masses flowable with the addition of heat. The invention relates to a method and a device for manufacturing a flexible strip of at least two different masses flowable with the addition of heat. The manufacture of such strips with the help of a strip casting device in a continuous method is, for example, a method step with the manufacture of soft gelatine capsules. By way of the use of differently colored gelatine masses, it is possible at the same time to achieve a certain pattern on the capsule casing.
By way of EP B1 653 979 (=WO 94/03316) there is known a comparable method of the known type with which the two different masses are poured out from a first and from a second application box. The second application box is at the same time positioned within the first application box such that the outer surface of the second application box and an inner surface of the first application box define a gap through which the first flowable gelatine mass may flow so that there arises a base gelatine strip. The second application box comprises at least one opening through which the second flowable gelatine mass may flow onto a part of the base gelatine strip so that there arises a patterned gelatine strip. A disadvantage of this method lies in the fact that the second mass is deposited onto the surface of the already completed formed strip of the first mass, since immediately after leaving the casting gap a cooling on the surface takes place.
A further disadvantage of the known method however lies in the fact that the possibilities for the patterning are greatly restricted and that practically only parallelly aligned patterns may be cast.
It is therefore the object of the invention to provide a method of the previously mentioned type with which, with simple design means, as homogeneous as possible patterned strip may be manufactured, wherein also complicated patterns may be realised. The device is to be as simple as possible in its handling and maintenance.
With the method according to the invention the two masses are not cast onto one another in layers from two separate casting openings bordering one another. Rather the second mass in the region within the casting gap, with the help of an injection nozzle is injected into the casting flow of the first mass. At the same time the first mass envelops the second mass completely or partly respectively the casting gap surrounds the opening of the injection nozzles completely or partly. On the one hand this leads to the fact that the second mass is practically completely enveloped by the firt mass. The coming-together of the two masses at the same time furthermore takes place at a location at which the casting flow does not yet come into contact with the surrounding air. This leads to a homogeneous combining of the two casting flows and thus in total to a homogeneous strip which subsequently may be processed without problem. Simultaneously the ejection of the second mass by way of an injection nozzle also however permits varied possibilities for forming differing patterns.
The ejection of the second mass may for example be effected intermittently so that the ejected material flow is partly interrupted. With this there may theoretically be manufactured strips with a point pattern or also xe2x80x9cleopardxe2x80x9d pattern.
Particularly interesting patterns may be drawn when the injection nozzles are moved during the ejection of the second mass. With this wave lines, serpentine lines but also closed loops and likewise may be drawn.
Particularly advantageously, with respect to the longitudinal direction of the casting gap, from several injection nozzles at least one second mass is ejected, wherein the injection nozzles are moved in opposite directions in a manner such that the material flows of the second mass intersect.
With such a guiding of the nozzles, intersecting lines may be produced on the strip. With this the only precondition is that the injection nozzles with the movement do not collide in that they for example are moved to one another in different planes or in an arc-shaped manner.
Finally it is also conceivable that with respect to the width of the casting gap from at least two injection nozzles arranged next to one another at least one second mass is ejected. This broadens the variety of possible patterns even further and it is furthermore also possible in the advance direction of the strip to permanently or temporarily improve the metering of the quantity of the second mass. Of course also however two different masses may be ejected so that the pattern comprises for example a different color on the front side and on the rear side of the strip.
The method is finally advantageously applied as a part of a capsule manufacturing method for manufacturing patterned soft capsules of two flexible strips with the rotary die method. With this it need not compellingly be the case of gelatine. Also other biopolymer masses may in the same manner be processed into capsules. The method is not only suitable for manufacturing patterned capsules but for example also for other products manufactured of a strip-like intermediate product, such as e.g. deep-drawn packaging inlays, bags and much more. The difference between the masses does not necessarily need to be restricted to the different color. It would indeed also be conceivable to combine masses of the same color but with different material properties, e.g. a mass with flourescing color pigments or a mass with different strength properties for producing a break-off location, and much more. Furthermore as many different masses may be ejected into the casting gap as are present injection nozzles.
The opening of the injection nozzle opens out within the casting gap, wherein it is preferably displaced back somewhat with respect to the plane of the casting gap.
The movable mounting of the injection nozzle in the casting container may be achieved in different ways. Particularly advantageously however the injection nozzle is arranged at the end of a supply tube which is led through a side wall of the casting container and which is linkedly mounted on this. In this manner also whole rows of injection nozzles may be mounted next to one another. As a bearing joint there serves for example a ball-and-socket joint so that the nozzles may also be pivoted circularly.
The supply tubes are advantageously individually or in groups movable with a manipulator arranged outside the casting container.
At least two injection nozzles are advantageuosly movably arranged next to one another in a manner such that they may intersect with respect to the longitudinal direction of the casting gap.
Further advantages and individual features of the invention result from the subsequent description of one embodiment example and from the drawings. There are shown in